I have one of the original Diretos as well as a Stages power meter. Here’s my experience.
A) I can’t use power match because there’s too much fluctuation. Maybe that’s because the Stages is single leg only and takes longer to estimate power.
B) I use ERG mode most of the time and it work OK but it’s not super great.
C) I turn off Elite’s smoothing as it seems to get in the way, but I do display smoothing - eg 3 second power on my Garmin
D) There seems to be a sweetspot of cassette and chainring position when doing workouts. I can’t use the big ring (53) for anything less than say about 100-150w as the Direto power won’t go that low reliably at my usual cadence of 90-100.
E) I usually run ERG mode in a small chainring (39) and mid way up the cassette.
F) ERG mode is a pain to use for short intervals and sprints. I can take about 10-12 secs at times to get up to the interval power. But I can ‘cheat the system’ a little by ramping up power just prior to the interval starting then backing off a little once the interval is underway
G) Power is pretty good. It’s within a few watts of my Stages if both are calibrated. The Direto needs a good solid 10 min warm up before calibrating. Thereafter it’s reliable for 2-3 weeks without another calibration.
H) It’s a fairly quiet unit which is nice. My fans are noisier than the unit.
Also note, some other brands will smooth the power output (e.g. Kickr’s) but it’s not real, it just looks that way.
I really feel it’s just a mid range trainer. One day I’ll upgrade to a higher end trainer, but for now it’s ok.